A component of foregoing type and a method for its production are known, for example, from DE 20023051.4.
DE 9700463 describes a method for producing green films for multilayer piezoceramic components with Ag/Pd internal, in which a PZT-type piezoceramic powder (PZT=lead zirconate titanate) is used.
The material and/or the process used to fire on the external electrodes that contact the internal electrodes should, in principle, be selected such that the electrode metal will not oxidize and the ceramic will not be reduced. For this reason, a precious metal or a precious metal alloy is customarily used as the electrode material.
DE 19945933 describes an exemplary method for producing external electrodes in piezoceramic components comprised of PZT ceramic and Ag/Pd internal electrodes. In this method, contacting of the Ag/Pd internal electrodes is accomplished using a metal paste that has a silver content of >65% and an organic binder, which is fired on at approximately 700° C. The firing on of the metal paste is conducted in an air atmosphere, because aromatic compounds contained in the organic paste binder cannot be completely degraded under reductive conditions. However, this method is not suited to a multilayer component with PZT ceramic and copper-containing internal electrodes, since at customary debindering and/or firing-on temperatures, reduction of the PZT ceramic and oxidation of the metallic copper are prevented under only one specific, very low oxygen partial pressure of <10−2 Pa. Thus, the Ag/Pd external electrodes cannot be used in a multilayer ceramic component with copper-containing internal electrodes.
DE 20023051 U1 describes a component that is less costly than multilayer piezoceramic components that are based on a PZT ceramic and Ag/Pd internal electrodes. This component uses copper-containing internal electrodes in place of the expensive Ag/Pd internal electrodes. However, DE 20023051 U1 does not indicate which material would be suitable for firing on external electrodes in a piezoceramic component with copper-containing internal electrodes.